1. Technical Field
The disclosure relates to dust cap assemblies for fiber optic ferules used in fiber optic connectors. Specifically, the dust cap assembly seals the fiber optic ferrule from contaminants during its incumbency and, upon removal, provides remedial cleaning of any foreign matter present on the ferrule when the dust cap assembly was initially installed. Additionally, the dust cap assembly functions as a terminator that reduces back reflection for testing the integrity of an optical cable assembly or as enabling a non-contact continuity test for fiber optic patch cables.
2. Technical Background
The capacity to send information over a wire revolutionized communication. Copper wire was the standard for more than 150 years, with ease of use and interconnection, but as bandwidth demand increased, it was necessary to seek alternative mediums. Optical fiber, developed and perfected over the past three decades, has made its presence felt, providing secure, high capacity signal transmission; in the past used primarily for long distance signal transmission due to its tremendous efficiency and security, but unable to easily leverage these attributes in more localized arenas. With developments in the joining of truncated fibers, suddenly optical fiber was becoming as versatile as copper. Optical fiber could be cut and easily rejoined via splicing, either by laser, electric arc or mechanical splicing, and by other mechanical processes. Of the mechanical processes developed, the ability to mate and de-mate an optical fiber to another optical fiber completed the versatility picture. Fiber optic ferrules and fiber optic connectors provided easy junction points in the field that tremendously increased the ease of use of optical fibers. Polishing optical fibers within appropriate ferrules is necessary to efficiently join two fibers end to end in such a way as to preserve the integrity of the optical signal with as little signal loss (attenuation) as possible.
To create a typical fiber optic cable assembly a fiber optic cable is terminated, a fiber optic connector is assembled at an end of the cable and the ferrule end face polished. The exactitude of the polished face of a fiber optic ferrule is such that any minute amounts of debris on that end face can block or decrease signal transmission or even damage the end face. Polished ferrule end faces can represent the end result of hours of manufacturing providing a polished ferrule end face to mate to another polished ferrule end face and thereby transfer signals from one fiber into another. Protecting the polished end faces of fiber optic ferrules is extremely important: protection from residual dust from the connector housing; protection from airborn contaminants in the manufacturing facility; protection from the effects of water, oils and chemicals; protection from the effects of temperature cycling, just to name a few. Dust caps as known in the art provide a shield from the physical contact of the delicate ferrule end faces with the outside environment, but do not inherently prevent ingress of moisture, remediate existing contaminants, and can actually deposit contaminants onto the very ferrule end faces they are designed to protect. Thus, there is an unresolved need for dust cap assemblies that will literally seal the optical ferrule end face, insuring the integrity of the factory polished ferrule, one that is inexpensive, easy to install and remove, and that prevents contamination by water, oil, dust, particulates, damage due to handling, etc.